Broaching machine



Sept. 12, 1944. H. H. GOTBERG `BROAG'HING- MACHINE Filed June 17, 194s 5Sheets-Sheet l .Sept 12, 1944. H. H. GOTBERG BROACHING MACHINE FiledJune 17, 1943 5 sheets-sheet 2 I IN VEN TOR.

A TTORNE Ys Sept. 12, 1944. H. H. GOTBERG Y 2,358,225

BROACHING, MACHINE Filed June 17, 194s 5 sheets-*sheet sV Y, E y .I rw

Sept. 12, 1944.

l H. H. GOTBERGV BROACHING MACHINE Filed June 17, 1943 s sheets-sheet 4JNVENToR.

NH A

H .Q mM l fvx dB Sept 12, 1944, H. H. GOTBERG 2,358,225

BROACHING MACHINE Filed June 17, 1945 -5 Sheets-Sheet 5 alla '47 zii@zia 55 INVENTOR.

ATTORNEYS Patented Sept. 12, 1944 'rear cette E.-

BRACHING Harry- H. Gotlerg; Detroit, Mich., assignor to ColoniaLBroachCompany',` Detroit, Mich., a corporation o'f` Delaware Application June'11,7,k

16 Claim" s.

'I'fie'f-`v present-:- invention relates to alv surface breachingmachiI-ie of the 'type'h admited to makea'` plurality of v successivecuts on 'afV single workL piece lwiththesamef breaching' tool, andthisapplication is afcOntiUatin-in-part' of' applicants" coper'idingapplication;- Sri'al-f No. 4782497, led' March-9, 1943i Itis theygeneral v:obb ect of the present invention trpI-Ovd improved: means for'operatingvand" cooking of f the tablelunderf bro'ach cutting'p'res#sure.

Another ob'jctlof'theinvention' is to provide improved means of the typementioned which; upon completion of onebycl' of movement," is@automatically placed a"`position"to"begin -a-neW cycle;

Other objects Landz advantages lof the invention willE become 1apparent` from the following speci- 'cation; the drawir'igs relatingthereto, andfrom thesclaifns'hereinafter set forth;

In the' drawir'ig'sfin'I which'like numerals are' usedto designate likeparts in the several viewst throughout:

Figure 1r is ai front elevation' of a vertical broaching-'machine to"which :the invention may' be-applied; l

Figure 2 is'a'sideiview of thebroaching'machine shown in Figure' 1;

Figure'is afragmentary sectional lView taken on" the 'line 3;-3 ofFigure 1, showing Ea plan View of-the workmovingxture;

l'gurev 4"isa-sectiona1 View; the upper portion ofwh'ich; is`tak`en'"ontheline 4-4- of Figure 3 andtheY lower portion of which is taken on the'centerlineof'the'machinej as 'indicated by the' lii'rev 4'-4' inli'gure'7;

Figure'5 is aside elevation of the work sup# p'ortingirture 'andadjustable abutment mounted on thetable;

Figure 6 is a' view' similar to Figure 5, showingV the partsv in a'diiferent position;

Figure 7 is'-aview taken ontheline 'It-I of Figure 4;'

1943,-:Seriall No.-49-1,.149y

(o1. stv-33)" Figure 81isfarfragmentarysection takenfon-ithe 'l line 8 8offligure-3; Y

Figures-9'; l'and 1-1 show"theform ofi/workpiece ifor which`theparticular emloodiinent@of"thefA invention.' illustrated 1 isconstructed;

FigurelZ- shows Aaffmodil'ed formy 'of y'abutmen-ti cam forr use when aArelatively fewnumberof". successiv'broachingf steps is requiredon eachworkpiece;

Figure 13' is" a hydraulic circuit diagram= show-w ing the hydrauliccircuit'rcntrols? and`cylinders provided toi effectautoiriatic"operation ofi the machine lthrough acompletercycle of'- breaching-1strokes; and 1511 Figure' A14 is*afragmentaiyvievof fa; portion of i thehydraulics circuit; showingf'theffmanner inf which th'ef indexingmechanisi'nfmus't ibea'modied" to"acconrimool'ate`r the'rnodied 4ffor'fnoffj abutment cam shown inf-Figure 12:1 20f Referring: to" the*drawings', -th'ei'irivention Y shown applied toa vertical broachirgmachine havi ing a main` frame? I II f and ave-'rtCalIy movable'-broachin'gf slide l I,4 which," is' formed integrally-f with'afhydraulic 'cylinder'l 2-fwhich is reciprocatedi 25 with referen'o'etoa"station`ary piston' under the control of the hydrauli'c'fcircuithereinafter 'dee' scribed.' Mounted on-'thevslide I`I"is-'a=faoe plateI2' carrying` a` pair'of toolf holdings channelshap'edfr'nembers'fl 3PIn the' present'instance, the? 30 machineis designed forloper'ating upontwoworkf-l piecessimultane'ously and' for simultaneously-cut tin'g two`relatively deep notches" in each"- vof th'- workpieces.Consequently;the-toolholding chan-'- nels v'supportiour broaohingfitoolsYI 4*.:

The frame ofthe machine'includesa forwardly projecting portion" havinga-E top surface I5 Vde-t iining a horizontal slideprrwhichfis mountedthe' work moving fand supporting'ftable A'I 6; l Apair of retainingplates 'I1 locatedat opposite ksidsof the"Y i0 work table is xed tothe-top' surface" I5` of 'the frame and ov'erliesfthe edges 'ofthe' worktable IBf to retain the table in position while permittin'git' toreciprocate towardv i and from 'the 1 bro'ach.

The Vtop frame member 'I 5"contains a longitulcf dina'lly extendings1ot"I8"at itscenter, into which projects a .downwardly extendingrib'I9"on' the table I6? Journaledin-a sleeve 20 on` the table isafcentrallylocatedfvertical pin 2|,4v the'lower end ofwhichfisfformed-into 'a rectangular shoe 5o 22` which' lies-belowthebottom surface ofthe' rib I9 and also 'below thebottom surfaceofthe member I5V ofthe frame.' The shoe 22, which is' of 'hardenedste'eLits"V in a" hardened steel `cam groove 23 formed` in av transverseslide"2|',A 55 which is mounted in suitable Ways on the under--J side ofthe frame member I5 for movement transverse to the movement of the tableI6. The slot 23 is diagonal, as best shown by dotted lines in Figure 3,in consequence of which transverse reciprocation of the slide 24 effectslongi tudinal reciprocation of the table I6.V Such transversereciprocation of the slide 24 is effected by a movable cylinder 26,which is keyed to the slide 24 by key 21 and which slides upon a pair ofaligned stationary piston rods 28 and 29 fixed to the frame of themachine.

The arrangement of the means for reciprocating the table so fardescribed is substantially like that disclosed in the patent to BenedictWelte et al., No. 2,225,191, except that the cam groove in the presentinstance is straight, rather than arcuate, and the angle of the camgroove 23 in the present construction is a self locking angle, that isto say it is such an angle that no force exerted on the table will beeffective to cause movementv of the slide 24 regardless of the positionof the shoe 22 in the'gro'ove 23.

VA. work holding xture is mounted upon the table I6 and'inc'ludes meansfor locating the position of the table duringwthe broaching operations.This xture comprises a main casting, indicated generally at 30. Thecasting 30 includes a flat base portion 3| secured to the table |6 inany suitable manner, as by bolts 32 and a pair of transversely alignedbosses 33 and 34, the outer ends of which are enlarged to form housings35 and 36, respectively. The casting 30 also includes a pair oflongitudinally extending housings 31 and 38 in longitudinal alignmentwith the housingsv 35 and 36, respectively, and projecting rearwardlytherefrom. It will be noted from Figures 3 and '7 that' the housings 31and 38 extend outwardly lat the sides beyond the side edges of the baseportion 3| olf the casing 3|),

thereby definingl a pair' of' side recesses beneath the housings 31 and38. The `casting also in,' cludes an upstanding work locating' block 39,which is of generally T shape, as viewed in plan in Figure 3, and a pairof reinforcing ribs 40 and 4| extending between the work supportingmember 39 and kthe bosses 33Qand 34, respectively. The work supportingmember, or block, 39 is provided with two right angle notches in itsforward corners, as -best shown in Figure 3, to receive a pair ofworkpieces 44. YSuitable hardened steel wear plates 45 are secured'tothe sides of the right angle notches to form the workpiece locatingsurfaces. i

The workpiece, as best shown in Figures 9, and 11, is of generallyrectangular configuration except that it has an arcuate or semi-circulargroove 45 in its upper surface. The particular operation to be'performedon the workpiece by the machine illustrated is a notchingY operation inthe forward corners to form` notches 46, the metal to be removed beingindicated by the dotted lines in Figures 11.

Each workpiece is held in position after yit is seated against the wearplates 45 by'means of a clamp 48, of generally right angle configurationwith its downwardly extending leg 49 arcuately curved to t thesemi-circular groove, or channel, 45. The clamp is heldin position bymeans of a stud 50 secured in the bottom of a recess 5| in the top ofmember 39 and extending through a suitable opening in the clamp 48. Theclamp is tightened by means of a nut 52 and a spring 53 surrounds thestud and tends to urge the clamp upwardly to facilitate release thereof.

It will be understood that the present invention is not limited in itsapplication to the par- Y ticular operation illustrated or to anypartic- One of the fixed abutments 56 has a longitudinal opening 58extending therethrough in which is slida-bly mounted a push rod 59, fora purpose hereinafter described.

When the table VI6 advances with the work supporting xture, one end ofeach of a pair of rods 60 carried by the fixture is adapted to abutagainst the fixed abutments 56 respectively and limit further movementof the table and workpiece toward the broach.

The rods 60 are rectangular in cross section andare slidable-inrectangular slots-6| in the housings 31 and 38 of the `fixture casting30. The slots 6| Yin the housings 31 and 38 are closed Iby meansof apair of plates 63 and 64, the forward en ds of which are enlarged tocomplete'the walls of the housings 35 and V36, re spectively. Thebottoms of the slots 6| vare provided with suitable slots 66, as bestshown in Figure 4, to receive pins 61 which arefxedrrespectively in therods 60. Coil springs 68 connect the pins 61 to stationary pins 69, thusnormally urging the pins 61 and,l consequently, the rods 60 to the left,as viewed in Figure 4, the slots 66 permitting such movement.

A: pair of stationary stops 10 secured to the stationary retainingplates |1'limits maximum movement of the pins 61 and rods 60 to theleft, as viewedk in Figure 4, to the position shown in that figure. Inthis position, the rods v60 are out of contact with the abutments56,vthus permitting the push rod 59 to project from its abutment 56. Y

YMeans are provided on the fixture for automatically controlling theposition of the rods 60 in order to limit movement ofthe work tabletoward the broach. Ihe means includes a relatively heavy shaft 12journaled in the two bosses 33 and 34 extending transversely to the.table I6. The ends of the shaft 12 project into the housings 35 and 36,where they are reduced in diameter, as indicated at 13, and receive apair of rotatablerabutment elements V.14. The two abutment elements,which are identical in construction,v are keyed to the shaft 12 by meansof a keyv15 and are peripherally formed of a plurality of stepped natsurfaces 16, 11, 18, 19, 89, 8|, 82, 83, 84, 85, 86 and 81,circumferentially distributed in sequence around the periphery and ofprogressively decreasing distance from the axis of the shaft 12. Thesurfaces are `so arranged that upon rotation of the shaft 12 any one ofthe flatsurfaces 16 to 81, inclusive, may be brought into position toabut against the ends of rods 60. In this connection, it will be notedthat the rods 60 extend in a line intersecting the axis of the shaft 12and, consequently, no pressure exerted between the'rods 66 and any oneof the surfaces 16 to 81, inclusive, will have a tendency to rotate theabutment elements 14.

The right-hand end of shaft 12, as viewed in Figure '1, beyondtherrotatable abutment element 14 thereon, is still further reduced indiameter, as indicated at 90, to receive a ratchet wheel 92, shown bestin Figure 4. Ther ratchet` twelve (12) -abutment surfaces are providedon the rotatable abutments 14. Accordingly, if two workpieces aresimultaneously machined, twelve (12) or less complete broaching cuts maybe made on each workpiece. It is, however, possible. to operate themachine on a single workpieceat a time, taking a pluralityof successivecuts on one broaching tool and then shifting the workpiece to the secondfixture and completing the cycle on the second or finish broaching tool.The particular hydraulic circuit mechanism hereinafterv describedis-designed to provide a two-stage .broaching operation on a singleworkpiece at a time in that manner. aAccordingly, the machineautomatically provides a cycle of eleven (11) broaching strokes and thenstops to permit the operator to shift the workpiece from one fixture tothe other. Then, on restarting the machine it makes a single broachingcut onthe work fixture with thev finishing broach and again stops,whereupon the operator removes the finished workpiece and places a newworkpiece in the first fixture, the parts then being in position torepeat the complete cycle.

It will be apparent that other variations in the sequence of operationof the machine may be made.

Regardless of the manner in which the machine is utilized, it will beapparent that during the last broaching stroke the parts will be in theposition illustrated in Figure 6, in which the fiat surfaces 81 on therotatable abutments 14 engage the rod 60. On withdrawal of the tablefromthe position shown in Figure 6, which withdrawal completes theentire cycle of operation, the rotatable abutments 14 will be indexed inthe position shown in Figure 4, in which figure all parts are shown inposition to start a complete cycle.

It will be apparent that the number of steps on the rotatable abutments14 may be varied to suit the needs of the machine and that differentshaped abutment cams may be substituted from time to time, as required.It will also beapparent, however, that if it is desired to perform acomplete multiple broaching cycle in which there are fewer than six oreight broaching strokes, it will be difficult, if not impossible, toindex the rotatable abutments 14 through a complete revolution for eachcomplete cycle by means of the pawl and ratchet constructionillustrated. Accordingly, when a relatively few numbenof strokespercycle isv requred it is preferred to construct the rotatable abutmentsin the manner illustrated in Figure 12, wherein is shown a `-viewcorresponding to Figure 4 but of a modified construction of an abutmentcam adapted foruse when the complete cycle contains only two broachingstrokes of the ram. Y g

In theA modified construction, thev rotatable abutment 14' Vis providedwith eight abutment surfaces, indicated 16', 11', 18', 19', 88', 8|',82' and 83', Aand the ratchet wheel 92' is provided with eightcorrespondingly positioned teeth so that one or more of the'faces 16' to83` will be in position to abut therod 60 after one tooth of the ratchetwheel has been engaged and shifted by the pawl |08' at the end of thewithdrawal stroke of the table I6'. TheV four abutment faces 1B', 18',80' and 82' of the rotatableabutment 14' are positionedat equaldistances from the axis of the abutment and are'separated from eachother by the intermediate abutment faces 11,'.19, 8I and 83', the lattergroup also being equally spaced from the axis of the abutment 14' butbeing lo- Icated closer to the axis ofthe abutment facesthanitherst-group.-v All other portions of the machine, except for aminor change in the hydraulic circuit hereinafter referred to, areidentical to the-machinedescribed in connection with Figures 1 to 11.A

, It Awill be apparent that when the modified form' of rotatableabutment shown in Figure 12 is employed, the work fixture will move fromitsV initial position, illustrated in Figure 12, toward the lbroachuntil the abutment 14' engages the Vrod 68'- and the latter has engagedthe fixed abutment 58,',not shown in Figure 12. 'Ihereby thefflrstbroaching stroke of the ram will take place. Upon completion of thefirst broaching stroke, the table will retract, and during suchretraction the pawl |08' will engage the next tooth of the ratchet wheelat 92' and shift the rotatable abutment in acounterclockwise directionuntil the abutment surface 11 is in position toengage the end of the rod60'. Thus, on

the next work advancing movement of the table I6' the table will move toa greater distance toward the broach than it would on its first strokeand, consequently,1the broach will make Vthe second cut in theworkpiece. On the 'second retraction ofthe work table, means,hereinafter described in connection with the hydraulic circuit,will-bring the machine to a stop, thus ending acomplete cycle ofoperations. However, the machine is in a position to be started on thesecond cycle, in which event the first broaching stroke will occur whenthe abutment surface 18' engages theV end of rod 68 V'and the secondbroaching-stroke will occur when the surface 'I9' engages the rod 6G. tolocate the table. It is apparent, therefore, that in the modifiedAconstruction four complete cycles are provided for each revolution ofthe rotatable abutment, instead of the single rotation as in theembodiment previously described. The mode of operation is, however, thesame.

It will be understood that any desired number of abutment surfaces maybeprovided upon the rotatable abutment so long asthere are at least sixand preferably eight surfaces, since effective operation 0f the pawl'and ratchet mechanism requires at least six and preferably eight teethon the ratchet wheel. AAccordingly,the rotatable abutment will beprovided with abutment surfaces which in number constitute an evenmultiple of the number of broaching strokes in a complete cycle but notless than six or eight. For example, if the complete cycle containsthree broaching strokes, the rotatable abutment may have six abutmentsurfaces but is preferably constructed with ninegsince the larger numberresults in a more satisfactory pawl and ratchet operation.

While-any suitable hydraulic control mechanisrn may be provided forcontrolling the operationofthe machine through its -cycle of movement,there is illustrated diagrammatically in Figure 13 one form of hydrauliccircuit which is adapted to operate the machine automatically througheleven (ll) successive cutting strokes and then stop the machine'toenable the workmen to shift a workpiece from the roughing fixture to thefinishing fixture. When the machine is then manually started on itsfinish broaching stroke, it completes that stroke and retracts the tableand again automatically stops to enable removal of the finishedworkpiece and insertion of a new workpiece. The parts are then in theposition to begin a' complete new cycle. of operation.

Referring' to Figure 13, the main-.breachingslidefcylinder is indicatedat |2 and the cylinder for operating the table is indicated at 26. Fluidis supplied through suitable lines and'valves to thesetwo cylinders froma pair of pumps |25 and |26, which are located within a tank or fluidreservoir |21.V Pumps |25 and |26 supply the breaching cylinder |2through a line |28, a pilot controll andr overload by-pass valve |29, aline y |30, a, speed control valve |30', a line |3|, and a pilotcontrolled four-way'valve |32 which has a pair of lines |33 and |134leading'to opposite ends of the cylinder |2. Line |34 is connecteddirectly'to the lower end of cylinder I2 through the piston rod |35,while line |33 connects to a foot valve |36 which, in turn, is connectedto the upper endV of. the cylinder |2 by a line |31- vand an auxiliarypiston rod indicated diagrammatically at |38. In the actualconstruction, the two piston rods |35 and |38 are concentric, and theVfluid to the upper end of the cylinder ilows between the two rods.'

Fluid from'th'e pump |26 flows through line |40- to a Ypilot controlledoverload relief valve |41` and'thence through line |42 to a pilotcontrolled four-way valve |43, which hasV a pair of lines |44 andM55-leading to the piston rods 28 and 29. respectively, of the cylinder26. The fluid which flows throughv pistonrod 28 passes into theVright-hand end of the Ycylinder 26 through an opening |46; while thefluid flowing through the piston rod 29 -iows into the opposite end ofcylinder 26 through an o-pening |41.

The pilot controlled overload relief valve |29 provides a clear,unobstructed flow between lines |28 and |30,\and thefstem |50 of theValve normally closes thelower port, which is connected through line andline |52 to the tank |21. The stem |50 is provided with a piston |53,which ltsthe valve housing and which is providedV with a small bleedopening |54. Accordingly, the pressure in lines |28 and |30 which existsin the main chamber of the valve housing |29 is transmitted through thebleedr open'- ing |54'in the piston |53 Vto the upper chamber of thevalve housing, thereby balancing the valve stem hydraulically. A lightspring |55 holds the balanced valve in its lower position, in which it.closesthe portconne'cted'to line |5|.

The space above'the piston |53 is connectedv through a passage |56 and aconnecting passage |51 to a ball check valve |56, which is normallv heldin position to block passage |51 by the action of af spring |59. If thepressure in lines |28 and |30f exceeds a predetermined amount determinedb v the setting of spring |59, the ball checkvalve 58 will open, therebyventing the fluid above piston |53 through a passage |60f and throughvan axial bore l6| in the valve-stem to the'tank lines' 5| and |52. Theflow of fluid through the bleed Opening |54 is restricted` and itcannot' replace the fluid above the piston |53 as fast as it dischargesto the reservoir past the check valve |58. Consequently, the pressureabove the piston |53'will be less thanthat below the piston, ,and thevalve stem will move upwardly, opening` the port connected to line |5|.This permits the fluid from pump |25 t0 discharge back to the tank atVery low Y pressure.

drops and the valve opens.

.The valve |30 may be any suitable form ofspeed control valve. It is setto pass a desired portion of the uid supplied to line |30 throughVline-|63 to the tank line |52, in order to decrease the speed of thebroaching stroke.

Except for its control upon the rate of iiow ofy uid' to the maincylinder '|2, the speed control valve |30 performs no function and canbe omitted if desired, in which event line |30 would be connecteddirectly to line |3|.

The four-way valve |32 is of the spring centered type, the spool |66being normally held in the position shown in the drawings by means of aspring, centering devicev including a pair of' washers |61 andY |68loosely'tting the stexnfof the valve. spool and aspring |69 `whichsurrounds the stem and bears against the two washers. Washer |61 isadapted to bear against the right-hand land of the valve spool |66,while formed on the valve casing.

When no pilot pressure'is applied to either end of the valve the springcentering device shifts the` valve spool to the position shown, in whichposition fluid may flow from line |3| into the annular groove |13 andthence through notchesV |14 in the central land of the valve spool andthence through notches |15 in the right-hand land of the valve spool to.channel |16', which plied to line |34. The left-hand land of the valvespool blocks return ilowfrom line |33 to thev tank line |52, which isalso connected by means of passageway |11 in the valve housing toannular channel |18.

When pilot pressure is applied` to the righthand end of valve |32through pilotlinel |80, the valve spool is shifted toits. left-hand end,during which movement sleeve |1| compresses springA l |69. In itsleft-hand position,.valve |32 permits iiow of liuid under pressure fromline4 |3| to line |34, inasmuch as the notches |15 lin the righthandland are shifted out of registry with the channel |16 when the spool isin its left-hand poi sition. In this position the left-hand land of thevalve spool clears channel |18, withthe result that fluid from line |33mayreturn to the tank through channel |18, passageway |11 and tank line|52.

When pilot pressure is admitted to the lefthand end of'valve |32through-pilot line |83, the

central land of the valvespool shifts to the right,

of channel |13, permitting flow of fluid under pressure from line |3| toline |33. Channel |18 remains closed by the left-hand land of the valvespool, and the right-hand land of the valve spool clears channel |16,thus permitting return flow from line |34 through channel |16 andpassageway |11 to the tank line |52.

The foot valve |36 contains a spring pressed check valve |84 which isnormally held closed by a light spring |85, in consequence of which arelatively free flow of fluid is permitted through valve chamber |86,passageway |81, past check valve |34, through passageway |88 and valvechamber |89 to line |31.

Communication between valve chambers |89 and is normally closed by meansof the valve spool |90, which is held in its lower position by means ofa spring |9| positioned within the holthis occurs, the pressure abovethe piston |53i 'y low valve spool. The valve contains a third chamber|92, which is fitted by a piston |93 on the valve spool |90, and a smallbleed opening 94 connects chambers |89 and |92 at a point beneath thepiston v|93 in the latter chamber.

-As a result of this construction, when line |33 is connected to thetank line |52 by valve |32 the pressure in line |31 from the upper endof cylinder I2 will be communicated from chamber |89 through the bleedopening |94`to the lower portion of the chamber |92 beneath piston |93and tend to raise the valve spool. However, the spring |9| is so setthat it will hold the valve Vspool closed against that pressure in line|31 caused by the weight of the broaching slide but will permit thespool to raise and open the valve at a slightly higher pressure. Thisprevents the slide from falling by its own weight during the broachingstroke if, for any reason, the resistance to its downward movementdecreases suiciently to permit it to so fall. l

When the machine is not in the broaching or return strokes of its cycle,valve |32 assumes its mid position shown in the drawings and therebyblocks return of fluid from line |33. This also prevents the cylinder l2from falling by gravity under these conditions.

' The pilot controlled overload relief valve 4|,

which connects lines Y|40 and |42, is identical inV line |91 to the tankin the manner described in connection with valve |29.

Four-way valve |43 is generally similar to four-v way valve |32 exceptthat the spool of valve |43 is not spring centered but, on the contrary,is held in`either one of its two extreme end positions by means of aspring pressed detent 200 which engagesv in either one of the pair ofnotches 20| and 202 in the valve spool.

When pilot pressure is admitted to the righthand end of valve |43through pilot line 205, the spool is shifted to its left-hand position,shown in the'drawings, in which position` fluid under pressure from line|42 flows between the central and right-hand lands on the valve spool toline |45 and thence to the left-hand piston rod 29 of the work tablemoving cylinder. At this time, fluid from the right-hand pistonrod 28 ofthe Work table moving cylinder returns through line |44 and the spacebetween the left-hand and central lands of spool 203 to channel 20B,which connects through a passageway 201 to a line 208. Line 208, inturn, connects through line |96 to the tank line |52. i

When pilot pressure is admitted to the lefthand end of valve |43 throughpilot line 209, valve spool 203 is shifted to its right-hand position,in which position iiuid under pressure from line V|42 iiows between thecentral and left-hand lands of the spool 203 to line |44. Return flowthrough line |45 passes between the central and right-hand lands tochannel 2 I0, which connects with passageway 201 and tank line 208.

When there is no pilot pressure applied to either end of valve |43, thevalve spool is held annular 'recess 238.

against displacement from thepositon it last assumed by means of thespring pressed latch 200. Y

Operation vof the above described main control valves to effect anautomatic cycle of operation of the machine isaccomplished through apilot controlled valve 'system which includes three main control valvesand a number of auxiliary valves. The three main control valves are themanually operated control valves 2I5, a table operated pilot valve 2|6for controlling the operation of the main breaching cylinder |2, and adual broaching slide controlled pilot valve 2|1-2I0 for controlling theVoperation of the work table.

The manual control valve 2 l5 comprises a generally cylindrical bodyhaving a central bore provided witli a plurality of axially spaced,circumferential grooves 220, 22|, 222, 223, 224, 225 and 226. Thegrooves 220 and 226 are simply to accommodate drainage, and have nofunction except to dispose of fluid which leaks past the end lands onvthe valve spool. Slidable within the central bore is a valve spool 230,which is provided with four lands 23|, 232, 233 and 234. The spool isnormally held in the `central or neutral position shown in the drawingsby means of a spring 236, which bears at one end'against the bottom of acup-shaped sleeve 231 xed to the right-hand end of the spool and at theother end against a washer 231 which loosely surrounds the valve stem.

'Ihe outer periphery of the sleeve 231 has an annular wide recess 238and a second narrow annular recess 239. A spring pressed plunger 240 isnormally urged into one or the other of the recesses 238 and 239. Thespool is shifted by means of an operating rod 242,'which is con-v nectedto an operating handle 243 pivoted in a convenient place on the frame ofthe machine.

' When no pressure is applied to the handle 243,

the spring 236 shifts the sleeve 231 and, con-v sequently, the spool 230to the position shown in the drawings in which a spring pressed plung`er 240 engages the right-hand edge of the wide When the handle 243 isshifted to the left to `start the machine, the valve spool is shifted byan amount equal to the Width of the annular recess 238, with the resultthat when the operator releases the starting handle the spool isreturned to its neutral position by spring 236. If the handle 243 isshifted in a, right-hand direction from the neutral position, the springpressed plunger 240 will engage in the annular recess 239 and retain thespool in its right-hand position until it is returned by operation ofthe handle 243.

The table controlled pilot valve 2|6 has a generally cylindrical bodyhaving a central bore in which is provided a plurality of annularchannels 250, 25|, 252, 253 and 254. Channels 250 and 254 are'connectedby passageway 256 to a pilot line 251, which is connected, in turn, to apilot line 258 extending to the tank |21. Valve 2|6 is provided with aspool 260 having a pair of lands. The spool 260 is operated by means ofa rod 26|, which is shifted in its left-hand direction, as viewed in thedrawings, by means of a lever 262 pivoted on a stationary portion of themachine and operatively connected to the push rod59 in the xed abutment56, shown best in Figure 4. Consequently, when the work supporting tablemoves into breaching position, push rod 59 will be shifted to the right,causing in the manner hereinafter described. A spring connected to thechannel 22| in valve 2I5 by a check valve 352 which, in turn, isconnected by line 353 to the line 35|.

When the manual control lever 243 is shifted to the right to itsemergency stop position, land V232 on the valve spool 230 shifts to theright of channel 222, thus permitting communication between channels22I'and 222. Channel 222 is connected by means of a line 355 and a line356 to the tank pilot line 258. Consequently, when the valve spool 230is shifted to the emergency stop position, fluid may ow freely throughthe check valves 350 and 352 from' the respective pilot lines |62 and|91 to the channel 22| of valve 2I5 and thence through channel 222andl'ines 355, 356 and 258 to the tank, thereby causing the valves |4|and |29 to open and relieve the pressure on the system. The check valves350 and 352 open freelyV against relatively light spring pressure topermit such flow, but they will not permit flow in a reversed direction.

The operation of the hydraulicl circuit is as follows.` In Figure 12,all of the parts are shown in the position they assume at the end of acomplete cycle o operation of the machine, at which time the machine isautomatically stopped in remove a nished workpiece and place a newworkpiece in one of the two work holding fixtures. Assuming that thepumps and |26 are operating, there will be no pressure applied to thebroaching cylinder |2 because the main control valve 32 for thebroaching cylinder is in its central position, in which the pressurefluid supplied through line I3I flows to the tank through channel |13,notches |14, notches |15, channel |16, passageway |11, and tank linek|52. The fluid trapped in the-upper end of cylinder I2 by valve |32 willhold the broaching cylinder in its upper position against the forceofigravity acting on the cylinder. The iluid under pressure from pump|26 will be transmitted through line |40, valve |4I, line |42 and valve|43 to line |45 and thence to the left-hand end of the work cylinder 26through piston rod 29. Sincel the work table will be at its extremeouter position and cannot move further, the pressure will build up to apoint at which valve |4| will open, venting the pressurel from line |40Ato the'tank through lines |96 and |52. Y n

The setting of valve |4| is such that it limits the pressure in theleft-hand end of cylinder 26 during these. circumstances toga safemaximum pressure. If at any time the pressure drops below the maximum,valve I 4 I will automatically close. In the meantime, high pressure ismain` tained on line |42 and the left-hand end of cylinder 26.

The source of pilot pressure for the entire circuit is line 360, whichis connected to line |42 which at all times is subject to the pressuredeveloped by pump |26. Line 360 connects to channel 252 of valve 2 I6.When the machine is stopped in the position shown in the drawings, thepressure from channel 252 is communicated from channel 253 and thence toa line 36| which,

inV turn, is connected to port 282 of valve 2|1. Line 36| is alsoconnected to the left-hand end of 'cylinder 346, thus holding the piston345`of the indexing mechanism in its right-hand position. The pilotpressure from port 282 of valve 2|1 is transmitted through passageway284 to lport 283 and thence through line 362 to the line 325, whichextends between check valve 324 and port 3I8 of valve 3|6.

Since no flow can occur between ports 3|8 and 3|1 of'valve 3I6 until thepressure has reached an amount determined by the setting of valve spring32|, the pilot pressure from line 363 will pass upwardly from line 325through the check valve 324 to line |31 and thence to the upper end ofthe breaching cylinder I2 and help maintain the broaching cylinder inits uppermost position. If the machine is left with the pump motorl shutolf for a substantial length of time, the leakage will permit thecylinder vI2 to sink downwardly under the influence of gravity and,accordingly, if that' has occurred the flow from line 362 throughline'325 and check valve 324 will prell the upper end of the cylinderand return the cylinder to its top position. Y

When cylinder |2 reaches its top position and can move no further, thepressure in the upper end of the cylinder in line |31 will build upsufciently to overcome the force of spring 32| in valve 3|6, therebypermitting the valve to open and provide communication between ports 3|8and 3 I 1.V Spring 32| is so adjusted, however, that the valve openingcannot occur until -the upper end of cylinder |I is entirely filled andthe pressureV increases in consequence of the fact that it can raise nofurther due to mechanical limitations.

When valve 3|6 opens, the pilot pressure then is transmitted from port3|1 through line 364 to a line 365,which extends tochannel 225 of valve2I5. At this point, the fluid is blocked so long as valve 2|5 is in itsneutral position illustrated 1n the drawings. Communication is alsoprovided between pilot line 364 and port 329 of valve 326 by means of aline 366,-but so long as the land 328'of valve 326 is in its stopposition, illustrated in the drawings, the fluid in line 366 and port329is blocked and cannot ow to port 330 or line 368, which connects port330 to channel 223 of valve 2I5. When valve 2 I5 is in its neutralposition, .pilot lines |62 and |91 from valves |29 `and |4|,*respectively, are also blocked at channel 22| of valve 2I5 and,consequently, the valves |29 and 4| will operate'only as pressure rel1efvalves. At this time there is no pressure on either pilot une zusV orV209 of va1ve |43 but the valvespool is retained tion by the springdetent lines and the tank.

The machine is started by shifting hand lever 243 to the left to itsstarting position. This shift moves valve spool 230 of rValve 2I5 to theleft, opening communication between channels 225 and224 and allowing theYpilot pressure in line 365 to flow through the valve to piloi-l line209 at the left-hand end of four-way valve |43. This pilot pressure willimmediately shift the valve spool 203 to its right-hand position.However, it should be noted thatif the starting handle 243 is shifted tostarting position before the cylinder is fully raised, valve 3|6 will beclosed, thus blacking communication between ports 3I1 and 3 |8 andpreventing any flow to the pilot line 365. Accordingly, valve 3|6positively prevents a shift in its left-hand posi- 200. Likewise, pilot|83 of valve 32 are connected to of Afour-wayvalveV |43 untilthevbroaching-cylinder is fully elevated by ythe flow of fluid throughline 325, valve 324, line 325', and line |31. As soon as the` spool ofvalve |43 shifts t0 its right-hand position, the fluid under pressure inline |42 is communicated through valve |43 to line |44 and thence`to-the right-hand end of the work moving cylinder 26 through the pistonrod 28 and opening |46. This will cause the work table to advance thework into broaching position, which positionvvill be determined byengagement of the flat surfaces 16 on the rotatable abutments 14 withthe rods4 60 which, in turn, engage the fixed abutments 56.

As soon as the work cylinder 26 and the table driven thereby begintomove, the operator may release the starting handle 243, whereuponspring 2,36 will return the handle and valve spool 230 to theirneutralposition, shown in the drawings. This will cut off the pilotpressure in pilot line 209 at the left-hand end of valve |43, but thespool 203 will remain in its right-hand position by reason of; theengagement of thepspring pressed detent 200 in notch 202.

, Upon completion of the table advancing movement, push rod 59 will bemoved to the right by the rods 60 and will shift thespool 260 of valve 2I6 to the left, thereby providing communication between channels 25| and252. `Pilot pressure will then flow from line 360 through valve 2I6 toline 310, which isconnected to channel 25| and thence to port 288 ofvalve 2|8. From port 288, the pilot pressure flows through passageway290 to port 289 and thence through line 309, port 3|0 of valve.30|, port3|| of valve 30|, and line |80 to the right-hand end of the four-wayvalve |32. The pilot pressure in pilot line |80 will shift the spool |66of valve |32yto its left-hand position, thus connecting pressure line|3| with line |34 and connecting tankliner-|52 with line |33. The fluidunderpressure in line |34 flows to the lower end of the breachingcylinder I2 and starts the downward or breaching stroke of the cylinder.During such broaching stroke the fluid in the upper end of the broachingcylinder returns through line |31, valve- |36, line |33, valve |32,

and the tank line |52. At this time, the return ow of fluid through line.|31 will lift the spool |90 of valve |36 oif its seat to permit thenecessary return flow.

It should be noted that the pilot pressure in line 310 which effectedthe last mentioned shift of the spool in valve |32 was not only directedto It will also be observed that when the worky table completed itsmovement and shifted valve spool`260 of valve 2I6, it caused a rockingmovement of bell crank 266 in a counterclockwise direction, thusreturning the lever I I9 to its righthand position by reason of aconnecting rod 265, bell crank 264, and rod I2'I.

Throughout the broaching stroke, fluid under pressure from pump |26 willbe maintained in the right-hand end of the work moving cylinder 26 eventhough the pilot pressure at the left-hand end of valve |43 iseliminated as the result of the shift of spool 260 in valve 2|6Y as wellas the return of the starting handle to neutraliposition. This is duetothe fact that the spool203 of valve |43 will be held in its right-handposition by engagement of the spring pressed detent 200 in the notch202, there being no -pressurein either of thefpilot lines` 205 and -209-of lvalve'2l'i3 `during the broachin'g stroke. Accordingly, the-workxture will be held in position'by-the'fullA operating pressureacting through the self-locking cam slot'23. f

On completion of the broachingstroke of cylinder I2, dog 2-19engages-finger 2 11 and rotates the spools of valves 2|'1 anol-2|6 inalcounterclockwise direction to a position in which the pilot pressurethen existing in. line 310r (spool 260 of valve 2|6-being in itsleftfhandposition) flows through port l288of valve 2|8 to port V29|ofthat valve and thence tothe pilot line 205,A which is connected at theright-hand end cfg-,four-way valve |43. The pilotpressurein line 42,95willl return the spool 203 of valve |43 to'l its left-hand position,shown in the drawings,thus causing the fluid under pressure from'linej I42- to pass through valve |43 to the line |45 and through piston-rod 29and opening |41 to the left-'hand end .of the work moving-cylinder 26,thereby'causing the work moving cylinderto rretract the work table untilthe cylinder assumes its fully retracted position, shown in the drawingsy l n Upon completion ofthe retractionof the Work moving cylinder26,*dog II8 engagesl andshifts lever I1I9 to the positionshown in thedrawings, thereby returning spool 260v of valve 2I6 to its right-handposition illustrated,- In that position, the pilot pressure in line 360is transmitted through valve2|6 toline '361|' and thencethrough port 262of valve 2| 1, port 285 of valve 2 I1j,line 300, port 302 of valve 30|,passageway 303, and port 305 to pilot line |83,wlf1ichis connected tothe left-hand end of thefourY-way valve |32.

The pilotppressure inline. |83 shifts thespool |66 of valve |32 to itsright-hand position,n in which'uid under pressurefromjline -3|'- passesto-line |33 and thence through valve |36 and line l k |31 to the upperend of'thebroaching cylinder I2 to cause the broach returning movement.The flow fat this time through the valve |36 visf-from chamber |86throughs-,passageway I81lpast the check valve I84and throughpassagewayfIB; and -chamber |89. During the broach returning movement,the fluid in the nlower end of the cylinder I2 returns through line |34and the valve |132 to the tank line |52. j Y u At thev time thebroachreturning movement is initiated, the pilot pressurerthen existing inline 36| is not only transmitted toport 282 of valve 2|1, but alsothrough branchv line 36| to Ythe lefthand end of the indexing cylinder346, thereby causing the piston 345 tomove to the right, carry'- Y ingAits ratchet pawl343. This right-,hand movement of the pawl y343 returnsthe rpawl and piston 345 to the position'sh'own ij-ngthe drawings Yandcauses the ratchet wheel 1342 and disc 33 1- toA r-.o-

tate clockwise one notch; This rotation of the .disc 331 retracts Vthenotch 339 out of engagement with the point 336 on pivoted disc 334,thereby causing the dog `to swing in acounterclockwiseY direction andshift valve spool 3271 of valve 326 tothe right, thus providingcommunication between'ports 329 and 330.V As willhereafter becomeapparent, as long as ports 3'29`and 330 `are incommunication witheach-otherthe machine will automatically repeat its cycle of operationsindefinitely; Y

A As soon as broaching cylinder I2 reaches vthe top 'of vits returnstroke, dog `218 engages finger `216,thereby rotating shaft 215andfspools 280 and 28| vof valves 2 I-1 and-2 [8in aclockwisedir'ection, return-ing. then to-a position shown inthedrawings. Pilot pressure then existing in line 36| may then iiow fromport 282 of valve 2I1 through passageway 284 to port 283 and thencethrough line 362 to line 325. Assuming that the cylinder I2 is in itsextreme upward position, the iiuid pressure in line 325 will then openvalve 316, permitting a iiow of uid from port 3|8 to port 3I1 and thencethrough line 364 to line 366. The pilot pressure in line 366 istransmitted to port 329 of valve 326 and thence to port 330 (land 328having been shifted to the right) from which it flows through line 368,channel 223 of valve 215, notches 315 in land 233 of the valve spool 230to channel 224, which communicates with the pilot line 209 for theleft-hand end of four-way valve l43. This pilot pressure in line 209will shift the spool 203 to its right-hand position in order to initiatethe work table advancing movement of cylinder 26, thus beginning a newcycle automatically. The new cycle will follow through in the mannerpreviously described and the piston 345, during such cycle, will operateto advance the pawl 343 and ratchet wheel 342 through one additionalnotch in a clockwise direction.` The cycle will continue to repeatitself with the particular construction shown eleven (11) times, oruntil the point 336 on pivoted dog 334 drops into notch 338 in the disc331. This will occur during the eleventh broach returning movement, andwill cause the spool 321 of valve 326 to shift to the left, into theposition illustrated in the drawings, in which position it blockscommunication between ports 329 and 330. VWhen the eleventh broachreturning movement is completed, all of i of valve 215 blocks thepassage of pilot pressure from line 365 to pilot line 209 for theleft-hand end of four-way valve '143. 'Y

During the first eleven complete cycles of operation, the work tablewill have moved on each advancing stroke a slightly greater distancetoward the broach than on the preceding advancing stroke, as the resultof the action of the surfaces 16 to 86, inclusive, on the rotatableabutments 14. At the end of the eleventh cycle of operation, thesurfaces 81 on the rotatablel abutments 14 will be in alignment with therods 60 but out of engagement with the rods because of the fact that thetable will be retracted. Since the machine is stopped at this point, theoperator may then shift the workpiece from the roughing xturerto thefinishing fixture and, having done so, he may again shift the lever 243to its starting position. The machine will then make a complete cycle ofoperation and again come to the stop, due to the fact that the ratchetwheel 342 will have returned to the position shown in the drawings, inwhich the point 336 of pivoted dog 334 rests in notch 339 of disc 331.At this stage, the finished broaching operation will have been completedand all of the parts will have been returned to the position shown inFigure 13. The finished l workpiece may then be removed from the machineand a new one inserted, and the machine is ready to begin a complete newcycle of operation.

It will be understood that the ratchet wheel 342 'will be provided withthe same number of teeth as there are provided abutment surfaces ori'the rotatable abutment 14 and that the disc 331 will be provided withnotches around its periphery at all points at which it is desired toabutment.

bring the machine to a stop. Thus, for example, when the modified form0f abutment cam illustrated in Figure-12 is employed, the valve 326 willbe provided with a ratchet wheel 342 having eight teeth, as shown inFigure 14, and the disc 331 will be provided with four equally spacednotches 339. The notches 339' are positioned to be engaged by the pawl334 during the return oi the broaching ram on every other broach returnstroke. Thus, the machine will stop at the completion of each pair ofbroach cutting operations in order to give the operator an opportunityto replace the finished work with a new workpiece.

It will be apparent that there is provided in accordance with thepresent invention an improved and highly efficient machine for making a.plurality of successive broaching cuts in a single workpiece. Themachine may be readily adapted to operate through any desired number ofbroaching strokes by simply changing the rotatable abutments, theratchets for driving the rotatable abutments, and the ratchet 342 anddisc 331 in the indexing mechanism of the hydraulicv circuit.

It will be apparent that various alterations and modiiications in theconstruction of the machine may be indulged in without departing fromthe spirit of the invention or the scope of the appended claims.

What is claimed is:

1. In a broaching machine for making a plurality of successive cuts on aworkpiece with the same broaching tool, a frame, a broaching toolmovable in a xed path, a work holding fixture movable with respect tosaid frame toward and away from the path of movement of said broach,means to force said xture toward said path, cooperating abutments onsaid xture and frame, respectively, adapted to limit movement of saidiixture toward said path, one of said abutments including a rotarymember having a peripheral abutment surface which at successive pointscircumferentially of said member is located at progressively decreasingdistances from the axis of rotation of said member, and means operablewhen said fixture is'withdrawn from said path to rotate said member by apredetermined amount in order to increase the nextV succeeding movementof the fixture toward said path.v

2. In a breaching machine for making a plurality of successive cuts on aworkpiece with the same broaching tool, a frame, a breaching toolmovable in a fixed path, a work holding xture movable with respect tosaid frame toward and away from the path of movement of said broach,means to force said fixture toward said path, cooperating abutments vonsaid fixture and frame, respectively, adapted to limit movement of said'xture toward said path, one of said abutments including a memberjournaled for rotation about an axis and having a periphery providedwith a. series of plane abutment surfaces located at progressivelydecreasing distances from said axis, and means operable when saidfixture is withdrawn from said path to rotate said member from aposition in which one of said plane abutment surfaces is in position toco-operate with the other abutment to limit movement of the xture towardsaid path to a position in which the next succeeding plane surface oflesser distance from said axis is in position to co-operatewith theother 3. In a broaching machine for making a plurality ofY successivecuts on a workpiece with the same broaching tool, a frame, a broachingtool operating abutments on said fixture and frame,

respectively, adapted to limit movement of said fixture toward saidpath, ene of said abutments including a member iournaled for rotationabout Van axis 'and having a periphery provided with a series ofplaneabutment surfaces located atproi `gressively decreasing distancesfrom said axis and intersecting, respectively, at right angles acorresponding series of equally spaced ce-planar radii extending fromsaid axis, and means eperable when saidfixture is Withdrawn from saidpath te rotate said member from a position in which VAone of said planeabutment surfaces is in position te ce-operate `with the other abutmentte limit mevementef the fixture toward said `path to a pe- Vsition inwhichthe next succeeding-plane surface -of lesser distancev from saidaxis is in position te ce-eperate with the other abutment. Y

4. In a breaching machine for making'a` plurality of successive cuts ena workpiece with the same breaching teel, a frame, a breaching toolmovable in a fixedipath, a werk holding fixture movable with respect tesaid frame toward and away from the path of movement of `said breach,means including a self-locking cam for moving said fixture toward saidpath, said cam being adapted te move said fixture to and lock itin a,plurality of breaching positions varying in distance from said path,ce-eperating abutments en said fixture and frame, respectively, adaptedto limit movement of said fixture toward said path, one of saidabutments including a rotary -member having a peripheral abutmentsurface which at successive peints circumferentially of 4said member isAlocated at progressively decreasing distances from the axis of rotationof said member, and means operable when said fixture is withdrawn fromsaid path te rotate saidmember by a predetermined amount in order toincrease the next succeeding movement of the `fixture toward said path,e Y

5. In a breaching machine for making a plurality of successive cuts en aworkpiecel with the .same breaching tool, a frame, a breaching toolmovable in a xed path, a work holding fixture .movable with respect tosaid frame toward and away from Vthe path of movement of said breach,means including a self-locking cam for moving vsaid fixture toward saidpath, said cam being adapted to move said fixture to and lock it in aplurality of breaching positions varying in distance from said path,co-eperating abutments en said fixture and frame, respectively, adaptedto limit movement of said fixture toward said path, one of saidabutments including a member journaled for rotation about an axis andhaving a periphery provided with a series of plane abutment surfaceslocated at progressively decreasing distances from said axis, and meansoperable when said fixture is withdrawn from said path to rotate saidmember from a position in which one of said plane abutment surfaces isin position te co-eperate with the other abutment tolimit movement ofthefixture toward said path te a position in which the next succeedingplane -surface of lesser distance from said axis is in `position tecooperate with the other abutment. 6.V In a breaching machinefor makinga Yplurality Aof successive cuts ena workpiece with the Ysame breachingtool, .a frame, a breaching tool .movable in:a,xedpath,.a `work holdingfixture movable with respect to said frame itowardand away fremrthe pathof movement of said breach,

`means including a self-locking cam for moving said fixture 'toward saidpath, said cam being vadapted te move-said fixture te and leckit in a4plurality of breaching positions varying in distance from said path,ce-eperating abutments onsaid fixture and frame, respectively, adaptedwte limit movement of said fixture toward said path, one of saidabutments including a member jeurnaled for rotation about an axis andhaving Aa periphery provided with a series of plane abut- -ment surfaceslocatedat progressively decreas- -ing distances from said axis andintersecting,

respectively, at right angles a correspondingseries of equally spacedco-planar radii extending from said axis, and means operable when saidfixture is withdrawnfrem :said path tel rotate saidmember from aposition in which one of said plane abutment surfaces is in position toco-eperate with the other abutment te limit movement of the fixturetoward said .path to va position in `which the next succeeding plane`surface of lesser distance from said axis is in position te co-operate25 :with the other abutment.

7. In a breaching machine fer'making a plurality ef successive cutsen aworkpiece with the same breaching tool, a' frame, a breaching toolmovable in a fixed path, a work holding fixture movable with respect tesaid frame toward and away from the path efmevement of said breach,

means to'ferce said fixture toward said path, a fixed abutment on saidframe, and abutment means en said fixture including a rotary member'having a peripheral abutment surface which at successivepoints'circumferentially.ef said member is located at progressivelydecreasing distances from the axis ef rotation of said member,

and means operable when said fixture is withdrawn from said path terotate said member by -av predetermined amount in order to increase the-next succeeding movement ef the fixture toward said path.

-8. In a breaching machine for making a plurality-ef successive cuts en:a workpiece with the same breaching tool, la frame, a, breaching ltoolmovable in a fixed path, a work holding -fixture lmovable with respectte'said frame toward and f' away from the path of movement of saidbreach, means to force said fixture toward said path, a -fixed abutmenten said frame, and abutment means on said fixture including a rotarymember having a peripheral abutment surface which at successive pointscircumferentially of said member is located at progressively decreasingAdistances from the axis of rotation of said member, means operable whensaid fixture is withdrawn from said path te rotate said member by apredetermined amount in order teA increase the next succeeding movementof the fixtureV toward said path, means f or moving said breaching toolin said path through a, breaching stroke, and centrol meansfor'initiating the breaching stroke ep- -eration of said last namedmeans, and said con- -trol means including an element operated 'by theabutment means on'said .fixture te initiate the breaching stroke whensaid abutment means engages said fixed abutment.

9. Inl a breaching machiner for making a plurality of successive cuts ena workpiece with `the same'broaching tool, a frame, a breaching toolmovable in a fixed path, a work holding fixture movable with respect'tosaid frame towardran-d `away from the path ofv movement of saidbreach, @means to force said fixture towardsaid path` a fixed abutmenton said frame, and abutment means on said fixture including'a rotarymember having a peripheral abutment surface which at successive pointscircumferentially of said member is located at progressivelydecreasingdistances from the axis of rotation of said member, means operable whensaid fixture is withl drawn from said path to rotate said member by apredetermined amount in order to increase the next succeeding movementof the fixture toward said path, means for moving said breaching tool insaid path through a breaching stroke, and control means for initiatingthe breaching stroke operation of said last named means,` said fixedabuttionary portion of the machine, a rotatable member jeurnaled on saidfixture and having a' periphery adapted to ce-operate with said firstmentioned abutment when said fixture is moved toward said position tolimit such movement, the periphery of said member at successive pointscircumferentially thereof being located at progressively decreasingdistances from the axis ef rotation of said member, and means operablewhen said fixture is withdrawn from said position for rotating saidmember by a predetermined amount inorder te increase the next succeedingmovement ef the fixture toward the breach.

1 11. In a breaching machine for making a plurality of successive cutsena workpiece with the same breaching tool, a frame, a breaching toolmounted on said frame for movement in a fixed path, a Work moving tablereciprocable on said frame toward and away from said path at rightangles to said path,V means connected te said table in approximatealignment kwith the center of the breaching tool for forcing the tabletoward the broach, a shaft journaled on the table and extendingtransversely te the direction of movelment of the table on oppositesides of the connection between the table and said means, a pair offixed abutments en the frame of the machine on opposite sides of thebreach, and a pair of ce-eperating abutment members on said shaft, eachof said co-operating abutment members having a peripheral abutmentsurface which at successive points circumferentially of said member islocated at progressively decreasing dise tances from the axis of saidshaft, and means to rotate said shaft a predetermined amount on eachreciprecatien of the table to cause said table to advance further towardsaid breach on each of a plurality of successive reciprocationsrbeforesaid ceeeperating abutments engage said fixed abutments.

12. In a breaching machine vfor making a plurality of successive cuts ona workpiece with the same breaching tool, a frame, a breaching toolmounted en said vframe for movement in a fixed path, a werk moving tablereciprocable on said vframe toward and away from said path'at rightangles te Vsaid path, means 'connected to said #table inv approximatealigmnent with the center of the breaching tool for forcing thetabletoward the breach, said means including a fluid pressure driving motorand a self-locking cam adapted to lock the table against movement inresponse te the breach cutting pressure, a shaft jeurnaled on the tableand extending transversely te the direction of movement of the table onopposite sides of the connection between the vtable and said means, apair of fixed abutments en the frame of the machine en opposite sides efthe broach, and a pair of ce-operating abutment members en said shaft,each of said co-operating abutment members having a peripheral abutmentsurface which at successive points circumferentially of said member islocated at progressively decreasing distances from the axis of saidshaft, and means te rotate said shaft a predetermined amount on eachreciprecatien of the table te'cause said table f to Vadvance furthertoward said breach on each of a plurality of successive reciprocationsbefore said ce-operating abutments engage said fixed abutments.

13. In a breaching machine fer making a plurality of successive cuts ena workpiece with the same breaching tool, a frame, a breaching toolAmounted on said frame for movement in a fixed path, a work moving tablereciprocable en said frame toward and away from said path at rightangles to said path, means connected to said table in approximatealignment with the center of the breaching tool for forcing the tabletoward the broach, a pair of abutments mounted en the frame at oppositesides of the path ef movement of the breach and a second pair ofabutments mounted on the table in position to ce-eperate with the firstpair, one of said pairs of abutments being fixed and the othercomprising a pair of elements mounted on a common rotatable shaft, eachof said elements having a peripheral abutment surface which atsuccessive points circumferentially of said member is located atprogressively decreasing distances from the axis of said shaft, andmeans to rotate said shaft a predetermined amount on each reciprecatienof the table `to cause said table te advance further toward said breachen each of a plurality of successive reciprocations before saidce-operating abutments engage said fixed abutments. l

14. In a breaching machine formaking a plurality of successive cuts on aworkpiece with the same breaching tool, a frame, a breaching toolmounted on said frame for movement in a fixed path, a werk moving tablereciprocable on said Y frame toward and away from said path at rightangles to said path, means connected to said table in approximatealignment with the center of the breaching teel for forcing the tabletoward the broach, said means including a fluid pressure driving motorand a self-locking cam adapted te lock the table against movement inresponse te the breach cutting pressure, a pair of abutments mounted onthe frame at opposite sides of the path of movement of the breach and asecond pair of abutments mounted on the table in position te co-eperatewith'the first pair, one of said pairs of abutments being fixed and theother comprising a pair of elements mounted on a commen rotatable shaft,each of said elements having a peripheral abutment surface which assuccessive peints circumferentially of said member is located atprogressively decreasing distances from the axis of said shaft, andmeans to rotate said shaft a predetermined amount on each reciprecatienof the table te cause said table to advance further toward said broachon each of a plurality of successive reciprocations before saidco-operating abutments enthe fixture toward broaching position, one ofsaid abutments including a rotatable member having a. plurality ofperipheral abutment areas each adapted to engage the other abutmentmember in one rotative position of said rotatable member, said abutmentareas being in number equal to an even multiple of the number of strokesof the Work fixture in a complete broaching cycle and not less than six,a ratchet wheel connected to said rotatable member and having the samenumber of teeth as there are abutment areas on the member, and a pawlmounted on said frame for indexing said ratchet wheel on eachreciprocation of said fixture, said abutment areas being located atvarying distances from the axis of said rotatable member to permit thexture to move progressively closer to the broach on each reciprocationduring a complete broaching cycle and on the indexing movement followingthe last broaching stroke of each cycle to limit movement of the fixturetoward the broach at the point required to make the first broaching cutof the next broaching cycle.

16. In a breaching machine for automatically CTI rality of broachingstrokes on the same workpiece, a stationary frame, a reciprocating workfixture adapted to move the workpiece toward and from the path of travelof the broach, means for reciprocating the work fixture including a camand a hydraulic piston and cylinder unit for operating the cam, said camhaving a self-locking portion adapted to hold the Work fixture againstreturn movement under the iniluence of the pressure exerted by thebroaching teeth, said means being adapted to move the work fixture intobroaching position in advance of each broaching stroke and to retract itfrom broaching position in advance of each broach return stroke, andmeans including a pair of abutments located on the work fixture and theframe, respectively, for limiting, movement of the fixture towardbroaching position, one of said abutments including a rotatable memberhaving a plurality of peripheral abutment areas each adapted to engagethe other abutment member in one vrotative position of said rotatablemember, said abutment areas being in number equal to an even multiple ofthe number of strokes of the work fixture in a complete broaching cycleand not less than six, a ratchet wheel connected to said rotatablemember and having the same number of teeth as there are abutment areason the member, and a pawl mounted on said frame for indexing saidratchet wheel on each reciprocation of said fixture, said abutment areasbeing located at varying distances from the axis of said rotatablemember to permit the fixture to move progressively closer to the broachon each reciprocation during a complete breaching. cycle and on theindexing movement following the last broachi'ng stroke of each cycle, tolimit movement of the fixture toward the broach at the point required tomake the rst broaching cut of the next broaching cycle.

EARRY H. GOTBERG.

CERTIFICATE oF CORRECTIODL Patent No. 2,558,225. September l2, 19ML,

HARRY H GOTBERG.

It is hereby certified that error appears in the printed specificationofthe above numbered patent requiring correction as follows: Page 2, firstcolumn, line 59, for "casing" read oasting; page 5, first column, line5l, for "uringing" read -urging; page?, first column, line 6h65, for"passagefay" read -passageway; page 8, first column, line 56, for"stopped in" read --stopped to; and second column, line 75': 'Or"blaeking" read --bloeking-; and that the said Letters Pat-ent should beread with this correction therein that the same may conform to therecord of the oase in the Patent office.

signed and sealed this 7th dey of November, A. D. 19ML.

Leslie Frazer (seal) Acting commissioner ef Patente.

